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From: std-unix@ut-sally.UUCP
Newsgroups: comp.std.unix
Subject: Re: tar or cpio?
Message-ID: <8202@ut-sally.UUCP>
Date: Tue, 2-Jun-87 00:43:42 EDT
Article-I.D.: ut-sally.8202
Posted: Tue Jun  2 00:43:42 1987
Date-Received: Sat, 6-Jun-87 10:07:34 EDT
References: <8126@ut-sally.UUCP> <8001@ut-sally.UUCP>
Reply-To: seismo!scgvacd!stb!michael (Michael Gersten)
Organization: STB BBS, La, Ca, USA, 90402
Lines: 48
Approved: jsq@sally.utexas.edu (Moderator, John Quarterman)

From: seismo!scgvacd!stb!michael (Michael Gersten)

I have some comments on Tar/Cpio.
 
First, Radio SHack does sell a tar that has an argument F for "here is a
file with the files you should read". Works with - for stdin. However,
you can't read the files from stdin and write the output to stdout,
although you can write to a named pipe (does mostly the same thing).

Secondly, whatever you use for backups should know about blocksizes.
In particular, if you lose one floppy, users should be able to restore all
the information on the other floppies. Tar does not do this--linking information
gets lost if this occurs. 

In particular,
	Floppy A has file X on it
	Floppy B has "Link X to Y"
If you lose floppy A, you've got garbage for Y. Worse, if you restore out
of order, no warning is given other than "Cannot link".

Finally, I feel that tar, in order to be usable as a backup facility, should
be required to unlink a file before it restores it. Otherwise, consider this:

Customer uses initialization floppy to initialize hard disk, which puts basic
commands (ls, tar, cp, etc) on disk, then restores the entire system from tarred
floppies.

Initialization system had /bin/l linked to /bin/ls (AT&T versions)
Customer had /bin/ls linked to lc, lf, lx (Berkeley versions), and the
AT&T as ls.old

After untarring, the Berkeley version was lost, and the AT&T version was under
all the names. Took me a while to figure this one out. Guess who the
customer was.

I do not consider backup/restore usable as they take 5 minutes per file to
recover individual files. I am not kidding; maybe R/S mucked something, but
that is ridiculus. Sure, you can get faster, but only if you first format the
disk, which takes 2 hours, and also do an incremental dump first.

[ Do you mean dump and restor?  (Or dump and restore?)  -mod ]

---
: Michael Gersten		seismo!scgvaxd!stb!michael
: The above is the result of being educated at a school that discriminates
: against roosters.

Volume-Number: Volume 11, Number 48